1. Field of the Invention
The present invention relates to a method of inhibiting hair growth, and more particularly to a method of inhibiting hair growth, by which hair growth on the legs and arms, and the like can be effectively inhibited, and use of a specific enzyme inhibitor for the preparation of a hair-growth inhibitor.
2. Description of the Background Art
A biological function of the scalp hair and body hair is to protect important organs of the head, chest, limbs and the like. With the development of clothes and protecting means, however, the organ-protecting function carried by the body hair has come to be unimportant.
The scalp hair is generally desired to be thick. In recent years, however, the tendency to prefer having no hair on, particularly, limbs and the like has been strengthened from the viewpoint of an aesthetic appearance. Therefore, various methods for removing the body hair have been developed and used. Specific examples thereof include mechanical removing methods making use of a shaver, hair plucker or the like, methods of using a depilatory to depilate body hair out of its root, methods of using a hair remover to remove body hair by its chemical reaction, etc.
However, these methods for removing the body hair are accompanied by the physical or chemical irritation of the skin, and the lastingness of their removing effects on the body hair is limited even though there is some difference between the methods. Therefore, such a treatment for removing the body hair must be conducted again after a certain period of time. It is thus desired to lighten the removal treatment of the body hair.
International Application WO98/25580 published Jun. 18, 1998 discloses a method for reducing hair growth by inhibiting the activity of a matrix metalloproteinase in the skin. The present invention intends the same purpose, i.e., providing a method of inhibiting hair growth. However, the researchers of the present invention found that hair growth is deeply influenced by the activity of elastase-like enzymes. Thus, there is fundamental difference in the present invention from the prior art, which provides a novel method characterized by inhibition of the activity of elastase-like enzymes.
Accordingly, it is an object of the present invention to provide a method of inhibiting hair growth, by which the growth of body hair can be effectively inhibited to reduce the number of removal treatments of the body hair.
In view of the foregoing circumstances, the present inventors have carried out an extensive investigation. As a result, it has been quite surprisingly found that inhibitors of elastase-like enzymes which digest elastin known as a structural protein in the artery, tendon, skin or the like, and inhibitors of neutral endopeptidases that are enzymes which digest opioid peptides such as enkephalin, and neuropeptides such as substance P and bradykinin have an excellent inhibitory effect on hair growth, thus leading to completion of the present invention.
According to the present invention, there is thus provided a method of inhibiting hair growth, which comprises administering an inhibitor of elastase-like enzymes or a neutral endopeptidase inhibitor.
According to the present invention, there is also provided use of an inhibitor of elastase-like enzymes or a neutral endopeptidase inhibitor for the preparation of a hair-growth inhibitor.
According to the present invention, an excellent inhibitory effect on hair growth can be achieved, and hair-growth inhibitors high in safety for the human body can also be provided.